1. Field of the Invention
The present invention relates generally to a coordinate indicating apparatus and a coordinate measurement apparatus for measuring an input position of the coordinate indicating apparatus, and more particularly, to a coordinate indicating apparatus such as a finger or a stylus pen and a coordinate measurement apparatus for measuring an input position of the coordinate indicating apparatus.
2. Description of the Related Art
Currently, devices such as a smart phone and tablet PC are actively under development with capability for a contact position measurement apparatus embedded therein. Specifically, the smart phone or the tablet PC generally includes a touch screen, and a user designates a particular coordinate of the touch screen by using a finger or a stylus pen. The user inputs a particular signal in the smart phone by designating the particular coordinate of the touch screen.
The touch screen may recognize input based on electricity, infrared light, ultrasonic waves and the like. For example, an electricity based device includes a Resistive type touch screen (R type touch screen) or a Capacitive type touch screen (C type touch screen). Among touch screens, the R type touch screen capable of recognizing a user's finger and a stylus pen has been widely used, but the R type touch screen is problematic in that there is screen glare due to an air space between Indium Tin Oxide (ITO) layers. More specifically, transmissivity of light penetrating a display is reduced due to the air space between the ITO layers, and external light reflection is increased.
Currently, the C type touch screen is also widely applied. The C type touch screen operates by detecting a difference in capacitance of a transparent electrode generated by a contact of an object. However, the C type touch screen has difficulty in physically distinguishing between a hand and a pen, resulting in an unintended operation error by a contact of the hand which may occur when the pen is used.
Software for distinguishing between the hand and the pen according to a contact area and a method including a separate position measurement apparatus such as an Electro Magnetic Resonance (EMR) technique as well as the C type touch screen has been used to solve the contact problem. However, software does not completely resolve the unintended operation error generated due to the contact of the hand, and implementing the method including the separate measurement apparatus increases size, weight, and cost of the device, by requiring additional components.
Therefore, there is a need for a technology capable of performing a determination without operation error when an object such as the stylus pen is used, without using a separate position measurement apparatus.